LRRK2 and Parkinson disease: The following studies have shown that valproic acid has the protective effects on the nigrostriatal dopamine system in several PD models, including 1-Methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine-induced (MPTP-induced) mice, lactacystin-induced mice, leucine-rich repeat kinase (LRRK2) R1441G transgenic mice and 6-OHDA-induced mice [93,94,95,96].